Monday, January 13, 2014

How warm days increase belief in the global warming scam

A new paper published in the political science journal Nature Climate Change says public opinions on global warming are unduly influenced by current temperatures and weather, but suggests this be used to the advantage of global warming activists by emphasizing to the public when days are warm [and not when they are cold].

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Abstract

Climate change judgements can depend on whether today seems warmer or colder than usual, termed the local warming effect. Although previous research has demonstrated that this effect occurs, studies have yet to explain why or how temperature abnormalities influence global warming attitudes. A better understanding of the underlying psychology of this effect can help explain the public’s reaction to climate change and inform approaches used to communicate the phenomenon. Across five studies, we find evidence of attribute substitution, whereby individuals use less relevant but available information (for example, today’s temperature) in place of more diagnostic but less accessible information (for example, global climate change patterns) when making judgements. Moreover, we rule out alternative hypotheses involving climate change labelling and lay mental models. Ultimately, we show that present temperature abnormalities are given undue weight and lead to an overestimation of the frequency of similar past events, thereby increasing belief in and concern for global warming.

Introduction

During a particularly hot summer in 1988, James Hansen testified before a congressional hearing on the dangers of global warming. The night before his testimony, committee members had opened the room’s windows and turned off the air conditioning, hoping the sweltering heat would underscore Hansen’s warnings and make the greenhouse effect concrete to anyone present1. This intuition, that today’s temperature would affect climate change beliefs, anticipates a more recent finding that subjective temperature does, in reality, affect reported beliefs in climate change.

Given that the challenge of reducing carbon emissions depends, in part, on changes in individual behaviour, it is important to understand the basis of global climate change perception and concern. Notably, individuals’ beliefs about the phenomenon seem to be constructed at the moment of elicitation, rather than simply retrieved from memory2. This is demonstrated by the fact that individuals are sensitive to normatively irrelevant features of the judgement context, including transient temperature3, 4, 5, 6, 7, 8. Mounting evidence shows personal experience with the daily weather tends to dominate more diagnostic but paler statistical information provided by experts9,10, 11, because the former is more vivid and accessible. Notably, perceived abnormalities in present temperature have been linked causally with changes in belief in global warming, an effect termed local warming12. Specifically, respondents who perceived today’s temperature as being warmer than usual exhibited greater belief in and heightened concern for global warming and also donated more money to a climate change charity.

Despite accumulating evidence that global warming judgements are influenced by short-lived temperature variation and local weather, the underlying psychological processes regarding how or why this relationship occurs have not been fully explored in the literature (see Supplementary Table 1 for a review of existing literature). There are at least three mechanisms by which transient, local temperatures may influence individuals’ judgements about global climate change. One mechanism suggests that choice option labels influence belief construction. For many issues, subtle changes in question terminology can result in pronounced differences in obtained answers13, 14, a phenomenon supported by the literature on attribute framing effects in decision research15, 16. Specifically, the term global warming, which has been used in previous studies, may prime heat-related cognitions, leading to biased judgements. Second, the local warming effect could be due to a knowledge deficit on the part of respondents, causing them to mistakenly believe that long-term climate and short-term temperature deviations are highly related. A third explanation, rooted in the cognitive heuristics literature17, proposes that individuals use less relevant but salient and available information (for example, today’s temperature) in place of more diagnostic but less accessible information (for example, global climate change patterns) in belief generation. Although this process, known as attribute substitution18, may seem highly irrational if done consciously and explicitly, other psychological process implementations give it greater plausibility. In particular, we suggest that unusually warm or cold weather conditions may increase the availability of other unusual warm or cold temperature events in memory, changing estimates of the frequency of such events, and thereby affecting respondents’ global warming attitudes. To preview our results, we find evidence for only the last of these three mechanisms.

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Conclusions

A growing body of research shows that transient temperature variation influences the public’s opinion of global climate change. We extend this research by examining several hypotheses regarding why this happens and exploring the mechanisms underlying the local warming effect. Our results suggest that an attempt to de-bias this robust effect will not be easy, as changes to survey terminology and enhanced scientific knowledge do not eliminate the effect of perceived temperature abnormalities. Further research is needed to determine how people’s belief in global climate change can be encouraged to develop over time from constructed, experienced-based reactions to more stable conclusions. Furthermore, although we find that attribute substitution is an important cause of the effect, rule out two alternative explanations and show that temperature priming can influence global warming attitudes, there may well be other sources of biases and heuristics that lead to the very stable local warming effect.

The local warming effect is an important real-word demonstration of how opinion on important issues can be constructed in response to a direct enquiry, rather than retrieved from memory. For climate change, a complex issue with contradictory coverage, individuals can draw weak conclusions and seem to reconsider their opinion each time they are asked a question. This characterization of climate change opinion and the apparent difficulties individuals experience when dealing with uncertain climate-related decisions have strong implications for public policy. For instance, these findings raise important questions regarding the potential role of the local warming bias in polling results. Our results suggest that recency and salience of warming constructs are promising ways of promoting heightened concern about climate change, at least among those whose beliefs or disbeliefs are not well established27. However, the opposite can also occur: the so-called snowpocalypse of 2010 in Washington DC resulted in increased media coverage of climate sceptics denying the existence of climate change. As climate change continues to cause an increase in the intensity of extreme weather fluctuations28,[False] the local warming effect may lead to even greater confusion among the general public. Weather variability will need to become better associated with heightened belief in climate change, though this new association will need to be accomplished through education and analogies, and not personal experience. If the United States is to take a stronger stance against climate change, forecasters may be well advised to make increasing warming abnormalities more cognitively available to the general public.